IBD rapidly rising among very young children in Canada

Last Updated: 2017-04-21

By Joan Stephenson

NEW YORK (Reuters Health) - Canada has one of the world’s highest rates of pediatric inflammatory bowel disease (IBD), and IBD incidence is growing fastest among Canadian children younger than 5 years, new research has found.

Incidence of IBD among these younger children (described as very-early-onset IBD or VEO-IBD) increased by more than 7% per year between 1999 and 2010.

“While IBD is still very rare in this age group compared to teenagers and young adults, we are seeing more children with VEO-IBD in our clinics, which reflects what we are seeing in this study,” lead author Dr. Eric Benchimol, a pediatric gastroenterologist at the Children’s Hospital of Eastern Ontario Inflammatory Bowel Disease Centre in Ottawa, Canada, told Reuters Health by email.

In a previous systematic review of international trends for pediatric IBD, Dr. Benchimol and colleagues found that global rates of childhood-onset IBD (Crohn’s disease, in particular) have increased rapidly over the past two decades, although most countries lack accurate estimates (http://bit.ly/2oQhq4a).

“We knew that the incidence of pediatric IBD was increasing in Ontario and around the world, but we didn’t have national numbers for Canada,” he said. “In addition, no study has been able to examine rates in very young children less than 5 years old, because they weren’t big enough.”

To investigate, Dr. Benchimol and colleagues in the Canadian Gastro-Intestinal Epidemiology Consortium conducted a retrospective cohort study using the provincial health administrative and population databases from five Canadian provinces (Alberta, Manitoba, Nova Scotia, Ontario and Quebec), which account for nearly 80% of the country’s population.

“By combining population-based databases of all residents of five Canadian provinces, we had a large-enough number of cases and we were able to look at rates in these younger patients,” he said.

Overall incidence per 100,000 children increased from 7.9 in 1999 to 10.6 in 2008, the researchers report in the American Journal of Gastroenterology, online April 18. This represents a nonsignificant 2.06% annual increase in childhood IBD cases in the overall cohort.

However, incidence increased sharply among children aged 6 months to 5 years, by nearly 7.2% per year (95% confidence interval, 2.8% to 11.6%), the first time an increase in this age group has been reported.

“We were surprised by the magnitude of the increase in children under 5, an age group that we previously almost never saw with IBD,” Dr. Benchimol said.

IBD prevalence has risen from 29 per 100,000 Canadian children in 1999 to 46 per 100,000 children in 2008, an increase of almost 60%. The increasing incidence of IBD among younger children may explain the increased prevalence of children younger than 16 living with the disease since the cases of VEO-IBD “would remain in the cohort for longer,” the researchers write.

There were some some substantial differences between the provinces in incidence, prevalence and trends over time. For example, Nova Scotia had significantly higher IBD incidence and prevalence compared with the other provinces.

A previous systematic review of studies published before 2010 found that only Norway had an incidence comparable to that of Canada, 10.6 per 100,000 children younger than 16.

Most regions around the world that have reported their IBD rates have found that their overall rate of childhood-onset IBD is rising, Dr. Benchimol noted. “In addition, Ontario, Scotland, and France have all shown increases in rates in children less than 10 years old,” he said.

“Similarly, most pediatric gastroenterologists in North America report seeing more young children with IBD over the past 20 years, although the United States has not reported trends in rates in any nationwide study,” he said.

Although studies by this group and others have documented a significant rise in IBD over the past 25 years, “unfortunately, none of these studies tell us why IBD is becoming more common,” Dr. Athos Bousvaros, associate director of the Inflammatory Bowel Disease Center at Boston Children’s Hospital, told Reuters Health by email.

The increase “is too fast to be simply due to genetics, so an environmental cause is suspected,” said Dr. Bousvaros, who was not involved with the current study.

“While the authors hypothesize the rise may be due to lower vitamin D levels, increased antibiotic use, or a Westernized diet, we really do not know,” he said.

“The interaction between environmental risk factors, the intestinal microbiome, and genetic predisposition are important areas under investigation,” the authors wrote.

Because young children have a shorter history of exposure to environmental risk factors than do older children and adults, “researchers may be able to better isolate environmental risk factors for these children, determine how they interact with genes or change the microbiome, and eventually prevent the disease,” Dr. Benchimol said.

The study had no commercial funding, and the authors reported no conflicts.

SOURCE: http://go.nature.com/2oovHE8

Am J Gastroenterol 2017.